The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Feb. 23, 1988
Filed:
Oct. 05, 1984
Norio Tomisawa, Hamamatsu, JP;
Nippon Gakki Seizo Kabushiki Kaisha, Hamamatsu, JP;
Abstract
A disc rotation control device for a compact disc player comprises a stable rotation detection circuit for detecting whether rotation of a compact disc is in a stable state or in an unstable state, a phase control loop for phase-controlling the disc rotation and direct control means for directly controlling the disc rotation. The disc rotation is controlled by the phase control loop when the disc rotation is in a stable state and, if the disc rotation has become unstable, the control of the disc rotation is switched to one by the direct control means. During the phase control, even if an EFM signal reproduced from a disc has become unavailable for some reason, preceding phase difference data is held and used for the disc rotation control.